This invention relates to a tone signal generation device used in an electronic musical instrument and other musical tone generation devices and, more particularly, to removal of a quantization noise contained in high frequency components of a tone generated from a tone signal generation device of a type in which a tone waveshape of plural periods is stored in a memory and a tone signal is generated by reading out the stored waveshape.
It has heretofore been practiced to store a full waveshape from the start of sounding of a tone to the end thereof or a waveshape of suitably selected plural periods in a memory and generate a tone signal of a high quality by reading out the stored waveshape (see e.g., U.S. Pat. No. 4,520,708).
In the system in which a tone waveshape is sampled with a limited resolution and stored in a memory, there arises the problem that a quantization noise is unavoidably contained in a high frequency region. For removing the quantization noise, it is conceivable to employ a filter of characteristics which attenuate high frequency components in the tone signal. This approach however is not desirable because signal components in the high frequency region also are removed by the filter. In actuality, there has not been made any effective proposal to remove such quantization noise.